The present invention relates to mass spectrometers for analysis of fluid (including gas) samples. More specifically, the invention relates to a micromachined mass spectrometer.
Mass spectrometers analyze a sample by ionizing at least some of the atoms or molecules making up the sample, and then isolating and detecting those ionized atoms or molecules that have a selected charge-to-mass ratio.
Broadhurst et al. teach a miniature motor pump mass spectrometer in U.S. Pat. No. 5,043,576. This spectrometer, however, is made up of many intricate and discrete components in a way which requires labor-intensive manufacturing and which reduces reliability. Spindt teaches, in U.S. Pat. No. 4,926,056, a microelectronic field ionizer fabricated with the techniques typically used to fabricate integrated circuitry. This field ionizer comprises a planar substrate having a gas outlet defined by a layer of electrically conductive material and another electrically conductive material on the substrate adjacent the outlet. The patent also teaches the use of an ion source array in an ion mobility spectrometer. However, the patent does not teach how to incorporate the field ionizer into a micromachined mass spectrometer.